With the exception of MRI, and to a certain extent MEG, biomagnetic imaging systems have been limited to use as laboratory research tools, due to the high cost and demands imposed by cryogenics and magnetic shielding. Nevertheless, biomagnetic imaging tools have demonstrated their potential for diagnosis in clinically important problems. For example, magnetocardiography (MCG) systems can be used to: (a) assess risk of life- threatening arrhythmias;(b) detect and characterize ischemic heart disease, (c) noninvasively localize cardiac activation, such as arrhythmia-causing regions, a pacing catheter and cardiac evoked field, or ischemic currents, and (d) study fetal heart function. To address the need for a noncryogenic multichannel magnetic imaging system capable of operating in an unshielded clinical environment, Physical Optics Corporation (POC) proposes to develop a Photonic Magnetometer-based Biomagnetic Imaging (PMBI) system. The key innovation is a high-performance photonic magnetometer (PM) that forms the building block of an imaging sensor array (ISA). The ISA consists of an array of hundreds of PMs, embedded in a vest that wraps around the patient's abdomen, enabling imaging of the back and side of the chest, as well as the front, which can significantly improve the detection and localization of abnormal cardiac function. In addition, the use of room- temperature sensors eliminates the need for costly, bulky cryogenics, enabling a more versatile and commercially viable imaging system. Eliminating 15 to 20 mm of thermal insulation that normally separates cryogenic sensors from the body surface improves the signal-to-noise ratio by a factor of up to 10. Noise cancellation algorithms, combined with high-order gradiometry, allow the PMBI system to operate in an unshielded environment, eliminating the need for magnetically shielded rooms that form a significant fraction of the cost of ownership ($1-2M) of current commercial systems. The cost of the PMBI system (~$10k) will be several orders of magnitude lower, enabling widespread use in clinical and point-of-care applications. Phase I will culminate in a demonstration of a proof-of-concept prototype of the PMBI system in laboratory testing. The Phase I limited-performance breadboard prototype will be assembled from readily available, low-cost components. Feasibility will be demonstrated through experimental verification of predicted prototype performance, and a path will be outlined for development of a custom-built, fully functional Phase II prototype that meets targeted performance goals for the final PMBI system. Processes for manufacturing and commercializing PMBI will be developed and tested in Phase II. PUBLIC HEALTH RELEVANCE: In many developed nations, cardiac disease is the leading cause of death. Magnetocardiography (MCG) is a safe, noninvasive, passive method for imaging the magnetic fields generated by the heart, that have been demonstrated to be accurate risk indicators for cardiac disorders such as ischemic heart disease. Unfortunately, MCG systems are almost completely absent from clinical practice due to the million-dollar price tag imposed by cryogenic cooling and magnetic shielding requirements. Physical Optics Corporation proposes to develop a low-cost, noncryogenic biomagnetic imaging system suitable for unshielded clinical and point-of- care applications.